Quadrille - 1:37 pm on Oct 3, 2011 (gmt 0)
That sounds pretty plausible; to the human eye, an elegant folder structure - with an elegant URL as a direct consequence - is a far more attractive proposition than a spammy mess.
Knowing how Google tries to emulate the human searcher, it is only reasonable that they'd have at least some success in identifying spammy URLs - I'm sure they try.
Of course the corollary is that CMS-generated scrambled eggs - even if not one of 15 duplicates - almost certainly do suffer; not necessarily a 'penalty' of any kind, simply because they are tougher to digest than a mom's-home-cooking simple URL.
That would certainly explain why pages with zero 'link building' and minimal anything else compete so easily with 'professional' cms sites. Or maybe they're just overcooked ;)